Wide cut rotary harvesters present inherent challenges in getting outboard severed crop materials to flow smoothly and without hesitation in a lateral direction toward the center of the machine before then turning rearwardly and moving through a central discharge opening into the conditioner rolls. Hesitation on the part of the crop materials as they “turn the corner” and move rearwardly into the conditioner rolls can cause problems, both in the quality of the finished windrows and the quality of cutoff being achieved by the rotary cutters. Due to the increased speeds at which rotary harvesters can travel compared to that of sickle-type machines, cutoff, feeding and control problems are exacerbated in rotary machines due to the dramatically increased volume of cut material flowing through the machines.
In one rotary cutter bed design, a group of inboard cutters of the bed are arranged with their axes of rotation directly in front of the opening to the conditioner rolls, inboard of conditioning structure on the rolls. One or more additional outboard cutters may be provided at each end of the bed and have their axes of rotation located outboard of the opening and the conditioning structure. In some situations, some or all of the crop streams end up against wall structure behind the outboard cutters.
This undesirable condition seems most likely to occur if the end cutters of the inboard group are so situated that their cutting knives project outboard of conditioning structure on the conditioning rolls as the knives are moving rearwardly in their paths of travel. It also seems to be the most pronounced when only a partial cut is being taken by the harvester wherein the outboard cutters at one end of the bed are presented with no standing crop material to sever. Cut materials that find their way behind outboard cutters tend to collect in that area and ultimately work their way forward, impeding proper cutoff and otherwise interfering with proper flow into the conditioner rolls. Sometimes, the accumulating material may even shoot out the ends of the cutter bed, rather than flowing to the center and being processed by the conditioner rolls. Such problems are magnified in machines having wide cutter beds with at least one cutter located outboard of the ends of the conditioning rolls, whereby crop material has a tendency to plug behind impeller cages and create excessive carry around behind the impeller cages and out the end of the header.